# 有限循环 for
# 未知循环 while 用条件控制循环
# 跳出循环 break(循环体) continue（当次循环）
from time import sleep

# while True:
#     print("hello world")
#     sleep(1)

# __iter__
#for it in "hello world":
#    if it == "l":
#        print(it)
#        break
